Different destabilized LiBH4 systems with several interacting components are being explored for hydrogen storage applications. In this study, hydrogen sorption properties of as-milled 6LiBH(4-)MCl(3) composites (M = Ce, Gd) are investigated by X-ray diffraction, differential scanning calorimetry and thermovolumetric measurements. The chemical interaction between metal halides and LiBH4 decreases the dehydrogenation temperature in comparison with as-milled LiBH4. Hydrogen release starts at 220 degrees C from the decomposition of M(BH4)(3) formed during milling and proceeds through destabilization of LiBH4 by in-situ formed MH2. The dehydrogenation products CeB6-LiH and GdB4-LiH can be rehydrided under moderate conditions, i.e 400 degrees C and 6.0 MPa of hydrogen pressure for 2 h without catalyst. A new 6LiBH(4)-CeCl3-3LiH composite shows promissory hydrogen storage properties via the formation by milling of CeH2+x Our study is the first work about reversible hydrogen storage in LiBH4-MCl3 composites destabilized by in-situ formed MH2. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.